The present invention relates to an image combining apparatus, particularly of a kind suitable for composing main image information obtained by imaging with a video camera and background image information recorded on a recording medium.
The chromakey technique (also called xe2x80x9cblue back composing techniquexe2x80x9d) is a conventional image composing method for combining, for example, images that are taken separately into an image that looks as if it were taken with a single video camera apparatus. In the chromakey technique, an object (a person, or the like) to become a main image is photographed with, for instance, a blue or green screen used as a background, and chroma data (chromakey data) is extracted from thus-obtained main image data. The chromakey data is combined with background image data that has been obtained preliminarily by imaging as data of a background, and resulting data is output.
The image combining by the chromakey technique has a drawback that an object to become a main image need to be photographed by using a chromakey back. However, this technique is now commonly used because it enables easy, real-time combining even in a case where an object to photographed is moving.
However, the chromakey technique has a problem that a combined image is not natural because it is difficult to make, for instance, the position and direction and the focus and zoom settings of a video camera when an object to become a main image is photographed completely equal to those when a background image is taken.
In view of the above, recently a system called a virtual studio has been proposed in which a background image is generated by computer graphics (CG). In this system, main image data of a main image taken with a video camera is combined with background data that is generated by computer graphics by the chromakey technique. A natural combined image can be obtained in this case because the background image data that is generated by computer graphics can be changed in accordance with the movement of the video camera.
This system has an additional advantage that it is not necessary to prepare a studio set etc. for imaging a background image because background data can be generated by a computer apparatus or the like.
However, to chromakey-combining main image data from a video camera with background data generated by computer graphics, three-dimensional computer graphics data needs to have three-dimensional data. There is a problem that the generation of three-dimensional data requires considerable cost and labor.
There is another problem that background image data other than that generated by computer graphics cannot be used as background image data to be chromakey-combined with main image data from a video camera.
The present invention has been made in view of the above problems, and an object of the invention is therefore to provide an image combining apparatus which can combine, naturally at a low cost, main image data from a video camera with background image data that has already been obtained by imaging.
To attain the above object, the invention provides an imaging system comprising imaging means comprising a camera stage capable of self movement and a video camera mounted on the camera stage; imaging operation control means for controlling an imaging operation of the imaging means; recording/reproducing means for recording, onto a recording medium, first image information that is produced by imaging with the imaging means and imaging control information indicating an operation control state of the imaging means at a time when the first image information is produced, and for reproducing the first image information that is recorded on the recording medium, the imaging control information being recorded onto the recording medium so as to be correlated with the first imaging information; combining means for combining second image information from the imaging means with the first image information from the recording/reproducing means; and control means for controlling the imaging means, the imaging operation control means, the recording/reproducing means, and the combining means, wherein the control means causes the recording/reproducing means to reproduce the first imaging information and the imaging control information that is correlated with the first imaging information and controls the imaging operation of the imaging means via the imaging operation control means based on the imaging control information, whereby the second imaging information that is output from the imaging means and the first imaging information that is reproduced by the recording/reproducing means are input to the combining means and combined there with each other.
In the above image system, the imaging control information may include camera setting information for controlling an imaging operation of the video camera and camera position information for controlling a movement operation of the camera stage.
The camera setting information may be information relating to color temperature.
The control means may control the camera stage based on the camera position information.
The recording/reproducing means may comprise first recording/reproducing means for recording the first imaging information and time information thereof onto a same, first recording medium, and imaging control information storing means for storing the imaging control information in a second recording medium so that it is correlated with the time information recorded on the first recording medium.
The imaging control information storing means may be able to store a plurality of time information and a plurality of imaging control information for each scene.
The combining means may combine the second image information with the first image information based on a chromakey.
The imaging means may comprise first and second camera apparatuses, and the imaging control information may include information for both of the first and second camera apparatuses.
According to another aspect, the invention provides an image combining method comprising the steps of producing first image information by imaging with imaging means that comprises a self-movable camera stage and a video camera mounted on the camera stage based on imaging control information supplied from control means; recording the first image information in recording/reproducing means; recording the imaging control information so that it is correlated with the first image information; controlling the imaging means and the recording/reproducing means based on the imaging control information so that second imaging information is output from the imaging means and the first imaging information is output from the recording/reproducing means; and combining the first image information and second image information with each other.
In the above image combining method, the imaging control information may include camera setting information for controlling an imaging operation of the video camera and camera position information for controlling a movement operation of the camera stage.
In the combining step, the first image information and the second image information may be combined with each other based on a chromakey.